TECHNICAL FIELD

This invention relates to storm sewage disposal systems and more particularly to such systems that filter and discharge water into the ground.

BACKGROUND ART

Urban development necessarily covers a substantial proportion of the surface of the ground with buildings, adjacent parking areas and interconnecting roadways. Subsequent to a rainstorm the consequences of this development are manifested in higher pea runoff volumes, increased turbidity and pollution in runoff water, decreased water infiltration into the ground, increased pollution in receiving water bodies, flooding ^' problems within waterways and even changes in the subsurface water level.

One study estimated that while 40% of rural rainfall was absorbed into the ground prior to urban development, as little as 10% of urban rainfall is now so absorbed.

Accordingly, the conveyance and disposition of increased and more polluted volumes of storm sewage is one of the major considerations that both a developer and an urban government must grapple with when contemplating urban development.

Storm sewage systems in the past have primarily focused on the treatment of more polluted water. An exception to this is U.S. patent No. 4,199,272 issued to E.H. Lacey for the purpose of recharging an aquifer. This patent shows a system and apparatus to discharge water into the ground. The system and apparatus comprises a motorized vehicle apparatus and attachment for laying a granular filter material and cleaning the same. The wheels of a motorized vehicle track on two parallel curbs. A trench is dug between the curbs. Along the bottom of the trench a series of wells are bored. The trench is lined with a plastic sheeting and then filled with a bottom layer of gravel and a top layer of sand. A convex ring of screening in the casing of the well restrains the gravel from

TE SHEET

entering the well. The Lacey apparatus is not suited for urban areas. Problems include its large surface area requirements and the equipment required for cleaning it.

DISCLOSURE OF INVENTION

According to the invention, there is provided a structure for filtering contaminated fluid comprising: a filter funnel having a top end having an intake opening; a central portion having sidewalls and a bottom end having a discharge opening, said discharge opening having a cross-sectional area in excess of 25 square inches; a unitized filter means positioned within the central portion of the funnel; and filter support means positioned below said filter means. According to another aspect of the invention, there is provided a structure for filtering and discharging storm sewage into a top end of a well casing thereunder comprising: a filter funnel having a top end having an intake opening, a central portion having sidewalls and a bottom end having a discharge opening; a filter means positioned within the central portion of the funnel; filter support means positioned below said filter means; and means to position the structure on the top end of the well casing.

BRIEF DESCRIPTION OF DRAWINGS

This invention is illustrated in particular and in a preferred embodiments in which:

Figure 1 is a perspective cross-sectional view of a structure for filtering a contaminated fluid; Figure 2 is a partial cross-sectional view of the structure of Figure 1 located in a manhole;

Figure 3 is a plan view of a bag containing filter material;

Figure 4 is an elevational view, partly broken away, of the bag shown in Figure 3;

Figure 5 is a cross-sectional view of a filter basket for multiple filters;

Figure 6 is a plan view of a filter basket for a singular filter material; Figure 7 is a cross-sectional view taken along lines "7- 7" of in Figure 6; and

Figure 8 is a perspective view of a hook assembly.

MODES FOR CARRYING OUT THE INVENTION Figure 1 is a perspective cross-sectional view, of a structure for filtering a contaminated fluid. A filter funnel 2 is shown positioned in a supporting structure 4. The supporting structure 4 is designed so that storm sewage will drain into the filter funnel. The supporting structure 4 is intended to include a relatively flat surface such as a garage floor or a concave surface that might be poured in a park which receives storm sewage after a rainfall. The supporting surface 4 has a circular opening 6 therein dimensioned to receive the filter funnel 2. The filter funnel 2 has a top end 8 having an intake opening 10. It also has a bottom end 12 and a discharge opening 14. A central portion 16 has sidewalls 18. A filter means 20 is shown within the central portion 16.

Figure 1 shows a filter means 20 having three porous sacks of filtration material. Each one of these three sacks is of the type shown in Figures 3 and 4. The number of sacks and the filtration material they contain may be varied to suit the needs of the application. A porous sack 22 is shown having grommets 24 through its top. A light rope 26 is threaded through the grommets 24. The rope 26 is of sufficient length that it may serve as a handle 28 to lift the sack 22 from the central portion 16. A clip or tie 27 in the rope 26 may be required to secure the closure of the sack 22. The porous sacks 22 allow granular filtration material 20 to be easily inserted and removed as a unit from the central portion 16.

When lifted the sacks elongate, allowing them to enter the intake opening 10 of the filter unnel 2. When in position the bags flatten, fully filling the central portion 16. Filter sacks 22 may contain different filtration media. Such filtration media would be selected from those generally available to remove a known contaminant. Pea gravel 29 might be chosen to remove the coarsest contaminants. Sand 30 might be chosen to remove finer contaminants which were not filtered out by the pea gravel 29. Charcoal 32 might be used to remove the finest of impurities from the fluid.

A mounting means 34 (see Figurae 2) is shown on the top end 8 of the filter funnel 2. The preferred mounting means is a rim 36. Bolts 38 may be used to secure the rim 36 in position. The bottom end 12 of the filter funnel 2 has a bottom rim 40 projecting horizontally inwards from the sidewalls 18. The bottom rim 40 supports a grate 42 positioned thereon. The filtration material 20 in sack 22 rests on the grate 42. A groove 44 around the bottom end 12 of the filter funnel 2 is dimensioned to receive a well casing 46 shown in broken lines. A well hole 48 may be cased or uncased. It may be left open or filled with gravel. It is however suggested that a top portion of the wellhole 48 be cased. Screws 64 around the bottom end 12 may be used to fasten the well casing 46 to the bottom end 12. Figure 2 is a partial cross-sectional view of the type of structure shown in Figure 1 located in a supplementary funnel. The supplementary funnel would most likely be made of concrete. The supplementary funnel shown is a manhole 50. Alternatively the supplementary funnel may be enlarged so that it comprises a reservoir (not shown) . A reservoir would be useful to hold storm water suddenly received from a downpour until it can be filtered into the well. The manhole 50 has a top end 52 having an upper opening 54 and a bottom end 56 having a lower opening 58. The lower opening 58 is positioned around the top end 8 of the filter funnel 2.

A bottom wall 60 of the supplementary funnel, or portion thereof, may be made of concrete poured on site i order to best fit the varying location of the well hole 48 The supplementary funnel shown is a manhole 50 having horizontal fluid discharge tube 602 therein. The well casin 46 is shown with a perforation 62 therethrough. One woul choose to perforate the casing at a porous ground layer abov or below the water table thereby choosing the zone o infiltration. In Figuare 2, the well casing 46 surrounds th bottom end 12 of the filter funnel 2. Screws 64 are used t fasten the bottom end 12 of the filter funnel 2 to the wel casing 46. A top grate 66 is used to cover the upper openin 54 in the top end 52 of the manhole 50. The top grate 66 ma be chained or hinged to the manhole 50 for safety reasons. I the manhole 50 is beneath a roadway 68 the top grate 66 wil have to be heavier.

Figure 3 is a plan view of a porous sack 22 containin filter means 20. An elevational view, partly broken away, o the porous sack 22 is shown in Figure 4. A rope 26 is strun between grommets 24 around the end of the porous sack 22. Th end is pulled closed and a tie 27 is used to hold it closed A length of rope 26 provides a handle 28.

Figure 5 is a cross-sectional view of a filter basket 7 for multiple filters 72. The basket enables the filter mean to be removed as a unit. The filter basket 70 is sized t removably fit within the central portion 16 of the filte funnel 2. The basket 70 has a porous bottom 74. The porou bottom 74 shown is supported by a bottom peripheral rim 76 The basket has a top portion 78 which is adapted to receive lifting means. The lifting means shown are opposed opening

80,82 suitable to receive a hook 92 as shown in Figure 8.

Alternatively, the lifting means might comprise a ba (not shown) removably affixed between said opposed opening 80, 82. Said bar would have an elevated central portion t ensure balanced lifting when it was hooked onto.

Figure 6 & Figure 7 respectively, are a plan view and a cross-sectional view of a different type of filter basket 70. This filter basket 70 does not require a bottom rim 40 or grate 42 to support it in the filter f nnel 2. Like the type of filter basket shown in Figure 5, it has a porous bottom 74 and is sized to fit within the central portion 16 of a filter funnel 2. It is supported by a top peripheral rim 86 which is too large to fit in the central portion 16. The top peripheral rim 86 is adapted to receive a lifting means. The adaption shown is diametrically opposed openings 88 in extended portions 90 of the top peripheral rim 86. A filter means 20 is shown within the basket 70.

Figure 8 shows a hook 92 which has a top portion 94, one or more central portions 96 and a bottom portion 98. Said portions are threaded together by screw threads 100. The top portion 94 is provided with a ring 102 suitable for a rope or a hook of a crane. The central portion 96 is a bar with one end having screw thread 100 projecting therefrom and the other end adapted to receive a similar threaded member. The bottom portion 98 is bent in the shape of a hook. It is suitable to fit within openings 80, 82 on the filter basket 70.

Having described preferred embodiments, it will be appreciated that the structure*s minimal surface area requirements, and its ease of filter servicing make its use practicable as part of a storm sewage system when land is subdivided for residential use, or as an upgrade to existing storm sewage systems where commercial development intensifies the demands on existing storm sewage systems. It is expected that the invention would be preferred where a falling water table is a real concern as well as in ecologically concerned communities.